From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shiva.jussieu.fr (shiva.jussieu.fr [134.157.0.129]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 07599201728 for ; Sun, 29 May 2011 08:06:10 -0700 (PDT) Received: from hydrogene.pps.jussieu.fr (hydrogene.pps.jussieu.fr [134.157.168.1]) by shiva.jussieu.fr (8.14.4/jtpda-5.4) with ESMTP id p4TFLUmb087060 ; Sun, 29 May 2011 17:21:44 +0200 (CEST) X-Ids: 165 Received: from lanthane.pps.jussieu.fr (lanthane.pps.jussieu.fr [134.157.168.57]) by hydrogene.pps.jussieu.fr (Postfix) with ESMTPS id DD784C3384; Sun, 29 May 2011 17:21:29 +0200 (CEST) Received: from jch by lanthane.pps.jussieu.fr with local (Exim 4.76) (envelope-from ) id 1QQho1-0002as-O0; Sun, 29 May 2011 17:21:29 +0200 From: Juliusz Chroboczek To: Jonathan Morton References: Date: Sun, 29 May 2011 17:21:29 +0200 In-Reply-To: (Jonathan Morton's message of "Sun, 29 May 2011 17:10:20 +0300") Message-ID: <7ipqn1bkhy.fsf@lanthane.pps.jussieu.fr> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Miltered: at jchkmail.jussieu.fr with ID 4DE2647B.000 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)! X-j-chkmail-Enveloppe: 4DE2647B.000/134.157.168.1/hydrogene.pps.jussieu.fr/hydrogene.pps.jussieu.fr/ Cc: bloat Subject: Re: [Bloat] tiny monsters: multicast packets X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 May 2011 15:06:11 -0000 > And the irony is that the lower speed is specifically chosen for > multicast in order to make sure all clients in range can hear them > reliably. It was my understanding that it was done for compatibility with older devices, since 2 Mbit/s is the fastest rate supported by pre-B spread-spectrum hardware. > 2) Unicast the packet to each attached host in turn, Both DVMR and the multicast part of BATMAN-adv do that for router-router links. A better link-layer solution, IMHO, would be to multicast (with ARQ) the packet at a reasonably high rate (say, the median of the STAs subscribed to the multicast group), and then unicast it to all STAs that failed to return an ACK. Interestingly, if the new multicast frame format is incompatible with the normal 802.11 format, then this scheme is compatible with legacy devices, which won't ever see the multicast frame and hence won't return an ACK. > So the workaround is to isolate the broadcast domains of wired > networks and wireless networks by making the home router into... > a router. Wireless on one subnet, wired on another, and so ARP > between the two turns into ARP to the router alone - much more > scalable. OpenWRT is your friend. -- Juliusz